Climate change is happening, and the urban poor are extremely vulnerable to its impacts. Demand for water and sanitation services in low-income urban areas is likely to increase, while flooding and water shortages may become more frequent.

This Practice Note outlines a rapid assessment method, developed for WSUP by Cranfield University, that can be used to plan the climate-proofing of a city’s water and sanitation services.

With more than half the world’s population now living in urban areas and with much of the world still urbanizing, there are concerns that urbanization is a key driver of unsustainable resource demands. Urbanization also appears to contribute to ever-growing levels of greenhouse gas (GHG) emissions. Meanwhile, in much of Africa and Asia and many nations in Latin America and the Caribbean, urbanization has long outstripped local governments’ capacities or willingness to act as can be seen in the high proportion of the urban population living in poor quality, overcrowded, illegal housing lacking provision for water, sanitation, drainage, healthcare and schools.

But there is good evidence that urban areas can combine high living standards with relatively low GHG emissions and lower resource demands. This paper draws on some examples of this and considers what these imply for urban policies in a resource-constrained world. These suggest that cities can allow high living standards to be combined with levels of GHG emissions that are much lower than those that are common in affluent cities today. This can be achieved not with an over-extended optimism on what new technologies can bring but mostly by a wider application of what already has been shown to work.

Seventy percent of the population of Dar es Salaam lives in unplanned settlements; and fifty percent of the residents of these informal settlements live on an average income of less than US$1/day. This fact is an important starting point for discussing the city’s vulnerability to climate change, and the strategies for adapting to this. The large number of people living in poor quality housing, frequently on land that is exposed to a variety of hazards, are socially, economically and environmentally vulnerable. The city also has severe shortfalls in its sanitation systems: estimates suggest that approximately 93 per cent of urban residents rely on pit latrines of various types, 5 per cent have access to septic tanks or sewerage, and the remaining 2 per cent have no formal excreta disposal facility. Adaptation responses need to take these issues into account if they are to respond to the threats posed by climate change – and to meet the needs of low-income urban residents.

The urban poor – already a vulnerable population – are the most susceptible to extreme heat. That is one of the findings from an interdisciplinary team of researchers from Arizona State University, NASA’s Johnson Space Center and the University of California at Riverside.

The team is engaged in a National Science Foundation-funded project exploring long-lasting heat waves and the relationship between temperature variations and socioeconomic variables in metropolitan Phoenix.

Remotely sensed imagery from NASA – taken from planes and satellites – is among the data being used to piece together a history of the metro Phoenix heat island, including how temperatures and vegetation patterns changed across the region from the early 1970s to 2000.

One finding is that poorer residents tend to live at the urban core, where vegetation is at a minimum and the presence of heat-absorbing and re-radiating asphalt and concrete is abundant, producing the most intense heat island effect. By contrast, people with higher incomes usually reside further away from the heart of the city and in homes surrounded by cooling vegetation.

Sharon Harlan, a sociologist in ASU’s College of Liberal Arts and Sciences’ School of Human Evolution and Social Change, is part of the team of educators, public health experts and social and natural scientists looking into how long-lived heat waves affect Phoenix residents. She stresses the seriousness of heat-related illness and death, as well as the likelihood that severity will rise. “Each year, heat fatalities in the U.S. occur in greater numbers than mortality from any other type of weather disaster. Global climate changes and rapidly growing cities are likely to compound and intensify the adverse health effects of heat islands around the world.”

She points out that the results of the team’s project could be used to help mitigate the damage, stating, “We want our research to be used to promote better decision-making about climate adaptation in cities.”

The remotely sensed data, which are used to not only look at past changes but also to build predictive simulations of what may occur, could be tools for, among others, city planners and emergency responders.

William Stefanov, senior geoscientist with Jacobs Technology in Johnson Space Center’s Astromaterials Research and Exploration Science Directorate, is providing the orbital view of the Phoenix area for the project.

“A lot of urban development is taking place around the world in arid or semiarid climates,” he says. “By studying Phoenix, researchers can better understand what these developing cities may face and how their environments may change as populations expand.”

The Coupling of Climate Change and Urbanization in India with a Focus on the Impact of Glacial Retreat, Part II

Health now and in the future

The main climate-related risks in the Hindu Kush-Himalaya region include the expansion of vector-borne diseases as pathogens are able to reside in new habitats in altitudes that were formerly unsuitable. Indian cities have already become reservoirs of vector-borne diseases such as malaria and dengue fever because of overcrowding and high rates of transmission (Revi, 2010). Cooking, sleeping, and living with 13.4 people per 45 m2 room area, as in the slums of Kolkata, India, places residents at high risk exposure of respiratory infections, meningitis, and asthma (Kundu, 2003). Water-borne disease accounts for 80% of all disease. Water-related infections can be transmitted in the following ways: through ingestion from drinking supplies, through lack of water for hygiene and via aquatic pathogens and insect vectors that are hydrophilic. Slum conditions promote the spread of disease through all of these means.

Studies have shown that the quantity and timing of runoff from snowmelt and glaciers directly and indirectly influence the frequency and prevalence of water-borne diseases. Climate projections predict a heightened gradient in precipitation between wet and dry seasons, with wetter wet seasons and accompanying increases in flash floods and drier dry seasons with sharp declines in water quantity. During the wet season, flooding is expected to flush feces and pollutants into water sources; during the dry season, there is expected to be increased incidences of starvation and malnutrition as well as hygiene-related diseases. Infrequent bathing is associated with scabies and bacterial skin infections, some of which can lead to acute glomerulonephritis (Heukelback et al., 2005). The entire Indian subcontinent will have to combat adverse health impacts of climate change and water shortage, particularly due to the lack of freshwater reservoirs of glaciers. However, the current intra-urban health disparities indicate that slum dwellers will suffer the most.

Water in Urban India

As of right now, India has a number of freshwater reservoirs, but the increasing population and overexploitation of surface and groundwater over the past few decades has resulted in water scarcity in many areas (Grail, 2009). India has the highest water footprint among the top rice and wheat producing countries. In addition, only 26.8% of domestic and 60% of industrial wastewater is treated in India (Grail, 2009). Once the land of the holy rivers, India is now known for the level of toxicity and pollution of its rivers. Local and national governments fail to effectively manage the water quantity and quality crisis in India.

Groundwater plays a pivotal role in shaping the economic and social health of many urban areas. In their study on the “Groundwater Situation of Urban India,” Patel et al. identified two major factors that determine whether a city can meet its water demand (Patel et al, 2007). The first is physical or geographic water availability, which is the availability of sufficient and good quality groundwater due to natural recharge or from canals and potable aquifers that store and supply water. Good quality here means free from salt-water intrusion. The second determinant is the ability of the urban area to survive on external sources. Patel et al. calls this factor economic scarcity rather than physical scarcity because in the event of water shortage, wells running dry for example, cities must obtain supplies, often at significantly high costs (Patel et al., 2007). In 2005, 65% of households across seven major Indian cities faced severe water deficiency and many cities were forced to reach out to distant water sources. Delhi and Chennai currently receive water from rivers that are 250 Km and 450 Km away, respectively (Grail, 2009). Smaller urban areas, where residents are mainly slum-dwellers, tend to have lesser say on water stored at distant reservoirs and lesser economic strength to pay for external water sources. If and when water resources decline further and surface water from glacial inflow is completely unavailable, international, national and local governments will have to rise to the challenge to save millions of urban residents.

This report outlines lessons learnt regarding the principal effects of climate change on 15 cities in low-income countries, and what makes them vulnerable to these effects. Coastal cities are susceptible to a rise in sea level and are made vulnerable by the low-lying land they are often built on, while dryland cities suffer from scarce water resources due to extended periods of climate change-induced drought. In these and other inland cities, the level of poverty, the rapid pace of urbanization and a lack of education about climate change increase vulnerability and aggravate the effects of climate change. Innovative urban policies and practices have shown that adaptation to some of these effects is possible and can be built into development plans. These include community-based initiatives led by organizations formed by the urban poor, and local governments working in partnership with their low-income populations.

(Dec. 17, 2009) — A Purdue University scientist has shown man-made changes to the landscape have affected Indian monsoon rains, suggesting that land-use decisions play an important role in climate change. Monsoon rainfall has decreased over the last 50 years in rural areas where irrigation has been used to increase agriculture in northern India, said Dev Niyogi, an associate professor of agronomy and earth and atmospheric sciences.

At the same time, heavily urban areas are seeing an increase in heavy rainfall. “In the rural areas, we’re seeing premonsoon greening occurring two weeks earlier than what it did 20 years back as the demand for agricultural intensification to feed India’s people increases,” Niyogi said. “The landscape has also moved in some places from what was once a traditionally rural setting to large urban sprawls. Both of these phenomena have affected monsoon rains.”

Niyogi used more than 50 years of rainfall data — spanning back to 1951 — collected by 1,803 recording stations monitored by the India Meteorological Department to determine different regions’ average yearly monsoon rain totals. While the mean monsoon rainfall for the entire country remained stable, Niyogi found that rainfall averages in India’s northwest region decreased by 35 percent to 40 percent from the historical mean during the past 50 years.

Analysis of soil moisture showed that before monsoon rains came, the northwest region had become as much as 300 percent wetter in recent years relative to the past 30 years, which has been attributed to irrigation from groundwater to sustain intensified agricultural production. This wetter surface causes cooling that weakens the strength of low pressure necessary for monsoons to progress into northern India. Satellite data showed that northern India is greening sooner than it had in the past.

That greening is creating a barrier for monsoons, which provide much-needed rain to replenish groundwater reserves being used for irrigation. “In this case, you need a warm, dry surface to advance the monsoon,” said Niyogi, whose findings were published in the journal Water Resources Research. “Because of increased irrigation, you now have a wet, green area, which does not allow the monsoon to reach far enough north.” Since that rain isn’t reaching the region, more irrigation is needed to sustain agriculture there. “Unless this is checked and controlled, the problem is going to become more and more severe,” Niyogi said. “With more irrigation, we will have less monsoon rain. With less monsoon rain, you will need more irrigation, and the cycle will continue.”

Urban areas, on the other hand, are being pounded with rain when it comes. Niyogi said there have been storms in some urban areas that drop as much as 37 inches of rainfall in a single day. Analysis of the areas that have received increases in heavy seasonal rainfall, based on Indian Meteorological Department and NASA satellite data, showed that those areas were experiencing fast urban growth. Areas where seasonal rainfall decreased were determined to have slow or no urban growth. “You only see these types of heavy rainfall events in those areas with heavy urbanization,” said Niyogi, whose research on the urban effect was published in the International Journal of Climatology. “The more urbanization spreads in those areas, the more of these heavy rain issues we’ll see and the more flooding will become a problem.” Niyogi said there are two theories on why that’s happening. The first says that urban landscapes create heat, which extends into the atmosphere and energizes storms. The second theory is that pollution created in urban settings interacts with passing clouds and increases rainfall.

Niyogi said the results of his study could have land-use implications elsewhere. “If urbanization is affecting the Indian monsoon season, it has the ability to affect patterns here in the United States,” he said. “This likely isn’t localized in India.” He added that India is hotter than the United States, and that may be exacerbating the issues. As global temperatures rise, other parts of the world could see similar climate changes — if they aren’t already — based on how land is used and developed. Chandra Kishtawal, of the Space Applications Center of the Indian Space Research Organization and a co-author on the papers, said he hopes the findings trigger discussions on the role of large-scale land-use planning in regulating climate change in India. “These kinds of things are not sustainable,” Kishtawal said. “They cannot continue in the long run.” The next step in this research is to examine landscapes in the United States to see if development has affected weather patterns historically. The National Science Foundation CAREER program and NASA’s terrestrial hydrology program funded Niyogi’s study.